2007 asme boiler and pressure vessel code asme section ii a sa 372 sa 372m (american society of mechanical engineers)

2008a SECTION II, PART A

SA-372/SA-372M

SPECIFICATION FOR CARBON AND ALLOY STEEL
FORGINGS FOR THIN-WALLED PRESSURE VESSELS
SA-372/SA-372M
(Identical with ASTM Specification A 372/A 372M-03.)

--``,,````,,```,```,,``,,`,,`,,`-`-`,,`,,`,`,,`---

1.

Scope
1.1 This specification covers relatively thin-walled
forgings (including gas bottles) for pressure vessel use.
Three types of carbon steel and six types of alloy steel are
included. Provision is made for integrally forging the ends
of vessel bodies made from seamless pipe or tubing.

therefore, each system must be used independently of the
other. Combining values from the two systems may result
in nonconformance with the specification.
1.3 Unless the order specifies the applicable “M” specification designation (SI units), the material shall be furnished to inch-pound units.

NOTE 1 — When working to the chemical and tensile requirements of
this specification, the influence of wall thickness and cooling rate will
necessarily eliminate certain forging sizes in each class.

2.

Referenced Documents
2.1 ASTM Standards:
A 275 /A 275M Test Method for Magnetic Particle Examination of Steel Forgings
A 370 Test Methods and Definitions for Mechanical Testing of Steel Products
A 388 /A 388M Practice for Ultrasonic Examination of
Heavy Steel Forgings
A 530 /A 530M Specification for General Requirements
for Specialized Carbon and Alloy Steel Pipe
A 788 Specification for Steel Forgings, General Requirements
E 112 Test Methods for Determining the Average Grain
Size
E 165 Practice for Liquid Penetrant Examination
E 290 Test Method for Semi-Guided Bend Test for Ductility of Metallic Materials
E 433 Reference Photographs for Liquid Penetrant
Inspection

NOTE 2 — Designations have been changed as follows:
Current
Grade
Grade
Grade
Grade
Grade
Grade
Grade
Grade
Grade
Grade
Grade
Grade

Grade
Grade
Grade
Grade
Grade
Grade
Grade
Grade
Grade
Grade
Grade
Grade

A
B
C
D
E Class 55
E Class 65
E Class 70
F Class 55
F Class 65
F Class 70
G Class 55
G Class 65
G Class 70
H Class 55
H Class 65
H Class 70
J Class 55

J Class 65
J Class 70
K
L
J Class 110
M Class 85
M Class 100

Formerly
Type
Type
Type
Type
Type
Type
Type
Type
Type
Type
Type
Type
Type
Type
Type
Type
Type
Type
Type
Type
Type

Type
Type
Type

I
II
III
IV
V Grade 1 Class
V Grade 1 Class
V Grade 1 Class
V Grade 2 Class
V Grade 2 Class
V Grade 2 Class
V Grade 3 Class
V Grade 3 Class
V Grade 3 Class
V Grade 4 Class
V Grade 4 Class
V Grade 4 Class
V Grade 5 Class
V Grade 5 Class
V Grade 5 Class
VI
VII
VIII
IX Class A
IX Class B

55

65
70
55
65
70
55
65
70
55
65
70
55
65
70

3.

Ordering Information and General
Requirements
3.1 In addition to the ordering information required by
Specification A 788, the purchaser shall include with the
inquiry and order a detailed drawing, sketch, or written
description of the forging and the areas of significant loading in the forging when required (see 6.4.2.2).

1.2 The values stated in either inch-pound or SI [metric]
units are to be regarded separately as the standard. Within
the text and the tables, the SI units are shown in brackets.
The values stated in each system are not exact equivalents;
701
Copyright ASME International

Provided by IHS under license with ASME
No reproduction or networking permitted without license from IHS

Licensee=Chevron Corp/5912388100
Not for Resale, 08/27/2008 14:59:35 MDT

A08


SA-372/SA-372M

2008a SECTION II, PART A

3.2 Material supplied to this specification shall conform
to the requirements of Specification A 788, which outlines
additional ordering information, manufacturing requirements, testing and retesting methods and procedures, marking, certification, product analysis variations, and
additional supplementary requirements.

ted. Attachment welding prior to heat treatment is not
permitted.
4.3.4 All quenched and tempered forgings shall be
subject to magnetic particle examination in accordance
with Section 7.
4.3.5 Heat treatment is to be performed after all
forming operations.

3.3 If the requirements of this specification are in conflict with the requirements of Specification A 788, the
requirements of this specification shall prevail.

5.

4.

Chemical Composition
5.1 Heat Analysis — The heat analysis obtained from
sampling in accordance with Specification A 788 shall
comply with Table 1.

Materials and Manufacture
4.1 Melting Practice:

5.2 Product Analysis — The purchaser may use the
product analysis provision of Specification A 788 to obtain
a product analysis from a forging representing each heat
or multiple heat.

4.1.1 The steel melting procedures of Specification
A 788 shall apply except that for Grade M forgings, only
steel that has been vacuum treated prior to or during the
pouring of the ingot, in order to remove objectionable
gases, particularly hydrogen, shall be used.

5.3 Starting material produced to a specification that
specifically requires the addition of any element beyond
those listed in Table 1 for the applicable grade of material
is not permitted. This does not preclude use of deoxidation
or inclusion control additions. Supplementary Requirements S1 and S2 of Specification A 788 shall apply.

4.2 Production Methods:
4.2.1 Methods for the production of gas bottles and
similar vessels shall include the cupping of slabs or plates,

the piercing of billets or plates, and the subsequent drawing
of cups so produced. Such semifinished forgings or seamless steel pipe or tubing shall be closed by spinning, swedging, or pressing. In all cases there shall be sufficient discard
to ensure soundness in the completed forging.

6.

Mechanical Properties
6.1 Mechanical tests for acceptance shall be made after
the final heat treatment of the forgings.

4.3 Heat Treatment:
4.3.1 At the option of the manufacturer, Grades A,
B, C, D and Classes 55, 65, 70 of Grades E, F, G, H, and
J forgings shall be normalized, normalized and tempered,
or liquid-quenched and tempered.

6.2 Tension Test — When tested in accordance with
Test Methods and Definitions A 370, the material shall
conform to the requirements of Table 2. The yield strength
shall be determined by the 0.2% offset method.

4.3.2 Grades K, L, M, and Class 110 of Grade J
forgings shall be liquid-quenched and tempered.

6.3 Bending Properties — Depending upon the outside
diameter, D, and the wall thickness, T, of hollow or bored
forgings, a bend test or flattening test will be required.

4.3.3 When normalized forgings are to be tempered,
or when forgings have been quenched, they shall be

reheated to a subcritical temperature and held for at least
1
⁄2 h/in. [25 mm] of maximum cross section.

6.3.1 For bored or hollow forgings with outside
diameters of 14 in. [355 mm] or less and with a D/T ratio
of more than 10.0, a flattening test is required. This shall
be carried out in accordance with Specification
A 530 /A 530M and Table 3. No breaks or cracks in the
test ring are acceptable until the distance between the plates
is less than that shown in Table 3.

4.3.3.1 Minimum tempering temperatures shall be
as follows:

--``,,````,,```,```,,``,,`,,`,,`-`-`,,`,,`,`,,`---

Grades E, F, G, H, J in Classes 55, 65, 70
Grade K
Grade L
Grade J Class 110
Grade M

1100°F
1100°F
1000°F
1000°F
1100°F

[595°C]

[595°C]
[540°C]
[540°C]
[595°C]

6.3.2 For bored or hollow forgings with outside
diameters over 14 in. [355 mm], or where the D/T ratio
is 10.0 or less at the manufacturer’s option, the flattening
test specified in 6.3.1, or a transverse bend test in accordance with Arrangement C of Test Method E 290 is
required. The bend test pin diameter shall be as specified
in Table 4. No cracks or ruptures in the test piece are
allowable when the test piece is bent through the required
angle.

4.3.3.2 If an attachment is welded onto a previously quenched and tempered pressure vessel, the post
weld heat treatment temperature of a weldment shall not
exceed the prior tempering temperature of the pressure
vessel. Fabrication welding of pressure shell is not permit702
Copyright ASME International
Provided by IHS under license with ASME
No reproduction or networking permitted without license from IHS

Licensee=Chevron Corp/5912388100
Not for Resale, 08/27/2008 14:59:35 MDT


2008a SECTION II, PART A

6.4 Orientation and Location of Test Specimens:
6.4.1 Test specimens representing vessel bodies or

shells shall be taken from a prolongation of a forging, from
test rings that have been heat treated with the forgings
they represent, or from a representative forging after heat
treatment in accordance with 4.3.

forgings in any continuous period up to 4 h duration in
accordance with 6.3.
6.5.3 For heat-treated forgings weighing 1000 lb
[450 kg] or more, one tension test shall be taken in accordance with 6.4.1 or 6.4.2 to represent each heat and not
more than ten forgings in a heat-treat lot. In addition,
hollow or bored forgings shall have one bend or flattening
test, taken in accordance with 6.3, to represent each ten or
fewer forgings from the same heat and heat-treatment lot.

6.4.1.1 Test specimens representing vessel bodies
or shells shall be located at a position corresponding to
the mid-wall location of the parallel side wall of the heattreated forging and shall be oriented parallel to the longitudinal axis of the vessel.

6.6 Hardness Testing:
6.6.1 Forgings under 1000 lb [450 kgm] in weight,
heat treated in a batch lot of up to 200 pieces (6.5.1) or
in a continuous furnace run covering up to 200 pieces in
up to four hours production (6.5.2) shall be subject to a
uniformity check by Brinell hardness testing, or an equivalent method. For this purpose, 10% of the furnace production shall be sampled and shall meet the minimum hardness
specified in Table 2 for the type and shall also be within
20 Brinell points of the hardness of the forging from which
the tensile test was taken.

6.4.1.2 A test ring shall be in the shape of a right
circular cylinder having the same diameter and wall thickness as the cylinders it represents. In addition, the test ring

shall be from the same heat of steel and be subjected to
the same heat treatment as the cylinders it represents. The
method of quenching the test ring must duplicate that of
the cylinders; if the cylinders are quenched from the outside
only, then the test ring must have its ends closed. The
length of test rings that will be liquid quenched must be
at least 24 in. [610 mm]. The ends of such test rings may
be vented to prevent pressure buildup during heat treating.

6.6.2 In the event that the test sample does not meet
these criteria, the remainder of that production group shall
be hardness tested and all of those forgings that fall outside
these limits shall be retempered or reheat-treated at the
manufacturer’s option and retested.

6.4.2 Test specimens representing vessel covers or
similar components may be taken from a full section prolongation of the cover, from a representative forging, or
from an integral prolongation when the part is contourmachined prior to heat treatment.

7.

Magnetic Particle Examination
7.1 All quenched and tempered forgings shall be subject
to magnetic particle examination after heat treatment. The
methods used shall be in accordance with Test Method
A 275 /A 275M.

6.4.2.1 Test specimens taken from full size prolongations or representative forgings shall be located at a
position midway between the center and the surface.
6.4.2.2 When forgings are contour-machined prior

to heat treatment so that highly stressed surfaces are
exposed, the test specimens may be taken at an equal
distance (t) from the nearest quenched surface as the highly
stressed area, but not less than 3⁄4 in. [20 mm]. The location
of the specimens from a second surface shall be at least
the greater of 11⁄2 in. [40 mm] or 2t.

7.2 Only direct current or rectified alternating (full or
half wave) current shall be used as the electric power source
for any of the magnetizing methods.
7.3 The forgings shall be free from linear indications
indicative of cracks. In case of doubt as to the type of
condition giving rise to linear magnetic particle indications,
they may be inspected for Type II indications referenced
in Reference Photographs E 433 when inspected by the
liquid penetrant method in accordance with Practice E 165.
Alternatively, some other suitable method for classifying
the indications may be used as agreed upon between the
manufacturer and the purchaser.

6.5 Number of Tests:
6.5.1 Up to 200 like forgings, each with a heattreated weight of less than 1000 lb [510 kg] when heat
treated in a single batch furnace charge, shall have one
tension test taken in accordance with 6.4.1 or 6.4.2 to
represent each heat. In addition, for hollow or bored forgings, one bend or flattening test shall be taken in accordance
with 6.3.

8.

Workmanship

8.1 If the thickness of a portion of the wall of a forging
is less than that specified, the forgings may be accepted
by the purchaser, provided that such irregularity will not
require lowering the allowable working pressure below
that for which the forging was designed.

6.5.2 Like forgings, weighing less than 1000 lb
[450 kg] each when heat treated in a continuous furnace,
shall have one tensile test taken to represent each heat and
not more than 200 forgings in any continuous period up
to 4 h duration. In addition, bored or hollow forgings shall
have one bend or flattening test taken per heat per 200
703

--``,,````,,```,```,,``,,`,,`,,`-`-`,,`,,`,`,,`---

Copyright ASME International
Provided by IHS under license with ASME
No reproduction or networking permitted without license from IHS

SA-372/SA-372M

Licensee=Chevron Corp/5912388100
Not for Resale, 08/27/2008 14:59:35 MDT


SA-372/SA-372M

2008a SECTION II, PART A

9.

Repair Welding
9.1 Repair welding shall be permitted when mutually
agreed upon between the purchaser and the manufacturer
and shall be performed in accordance with all the requirements of the applicable code or rules of construction.

10. Keywords
10.1 alloy steel forgings; carbon steel forgings; gas
bottles; pressure vessels; thin wall

TABLE 1
CHEMICAL REQUIREMENTS
Composition, %
Elements

Grade A

Grade B

Grade C

Grade D

Carbon
Manganese
Phosphorus, max
Sulfur, max
Silicon
Nickel

Chromium
Molybdenum

0.30 max
1.00 max
0.025
0.025
0.15–0.35
...
...
...

0.35 max
1.35 max
0.025
0.025
0.15–0.35
...
...
...

0.48 max
1.65 max
0.025
0.025
0.15–0.35
...
...
...

0.40–0.50
1.40–1.80
0.025
0.025
0.15–0.35
...
...
0.17–0.27

Carbon
Manganese
Phosphorus, max
Sulfur, max
Silicon
Nickel
Chromium
Molybdenum

Carbon
Manganese
Phosphorus, max
Sulfur, max
Silicon
Nickel
Chromium
Molybdenum
Vanadium

Grade E
Classes

55, 65, 70

Grade F
Classes
55, 65, 70

Grade G
Classes
55, 65, 70

Grade H
Classes
55, 65, 70

Grade J
Classes 55,
65, 70, 110

0.25–0.35
0.40–0.90
0.025
0.025
0.15–0.35
...
0.80–1.15
0.15–0.25

0.30–0.40
0.70–1.00
0.025

0.025
0.15–0.35
...
0.80–1.15
0.15–0.25

0.25–0.35
0.70–1.00
0.025
0.025
0.15–0.35
...
0.40–0.65
0.15–0.25

0.30–0.40
0.75–1.05
0.025
0.025
0.15–0.35
...
0.40–0.65
0.15–0.25

0.35–0.50
0.75–1.05
0.025
0.025
0.15–0.35
...

0.80–1.15
0.15–0.25

Grade K

Grade L

Grade M
Classes
85 and 100

0.18 max
0.10–0.40
0.025
0.025
0.15–0.35
2.0–3.3
1.00–1.80
0.20–0.60
...

0.38–0.43
0.60–0.80
0.025
0.025
0.15–0.35
1.65–2.00
0.70–0.90
0.20–0.30
...

0.23 max
0.20–0.40
0.020
0.020
0.30 max
2.8–3.9
1.50–2.00
0.40–0.60
0.08 max

--``,,````,,```,```,,``,,`,,`,,`-`-`,,`,,`,`,,`---

704
Copyright ASME International
Provided by IHS under license with ASME
No reproduction or networking permitted without license from IHS

Licensee=Chevron Corp/5912388100
Not for Resale, 08/27/2008 14:59:35 MDT


2008a SECTION II, PART A

SA-372/SA-372M

TABLE 2
MECHANICAL REQUIREMENTS

Tensile Strength,

ksi [MPa]

Type

--``,,````,,```,```,,``,,`,,`,,`-`-`,,`,,`,`,,`---

Grade A
Grade B
Grade C
Grade D
Grades E, F, G, H, J
(Class 55)
Grades E, F, G, H, J
(Class 65)
Grades E, F, G, H, J
(Class 70)
Grade J (Class 110)
Grade K
Grade L
Grade M (Class 85)
Grade M (Class 100)
A

Yield
Strength
(0.2% Offset),
ksi [MPa], min

Hardness,
HB, min A

60–85 [415–585]
75–100 [515–690]
90–115 [620–795]
105–130 [725–895]
85–110 [545–760]

35
45
55
65
55

[240]
[310]
[380]
[450]
[380]

20
18
15
15
20

121
156
187
217
179

105–130 [725–895]

65 [450]

19

217

120–145 [825–1000]

70 [485]

18

248

15
20
12
18
16

277
207
311
217
248

135–160 [930–1100]

100–125 [690–860]
155–180 [1070–1240]
105–130 [725–895]
120–145 [825–1000]

110
80
135
85
100

[760]
[550]
[930]
[585]
[690]

When required by 6.6.

TABLE 4
MAXIMUM PIN DIAMETERS AND MINIMUM ANGLE
FOR BEND TEST

TABLE 3
DISTANCE BETWEEN PLATES FOR FLATTENING
TESTS A
Type
Grade A
Grade B
Grade C

Grade D
Grades E, F, G, H, J (Class 55)
Grades E, F, G, H, J (Class 65)
Grades E, F, G. H, J (Class 70)
Grade J (Class 110)
Grade K
Grade L
Grade M (Class 85)
Grade M (Class 100)
A

Elongation
in 2 in.
[50 mm],
min, %

Distance Between Plates,
min, in. [mm]
0.50
0.6
0.65
0.7
0.7
0.8
0.8
0.9
0.8
0.9
0.7
0.8

D
D
D
D
D
D
D
D
D
D
D
D

Type

Pin Diameter

Angle, deg

Grade A
Grade B
Grade C
Grade D
Grades E, F, G, H, J (Class 55)
Grades E, F, G, H, J (Class 65)
Grades E, F, G, H, J (Class 70)
Grade J (Class 110)
Grade K
Grade L

Grade M (Class 85)
Grade M (Class 100)

2t
2t
3t
4t
4t
4t
4t
6t
4t
6t
4t
4t

180
180
180
150
150
150
150
150
150
150
150
150

D p outside diameter.

705
Copyright ASME International
Provided by IHS under license with ASME
No reproduction or networking permitted without license from IHS

Licensee=Chevron Corp/5912388100
Not for Resale, 08/27/2008 14:59:35 MDT


SA-372/SA-372M

2008a SECTION II, PART A

SUPPLEMENTARY REQUIREMENTS
One or more of the following supplementary requirements shall apply only when specified
by the purchaser on the inquiry, contract, or order. Details of these supplementary requirements shall be agreed upon by the manufacturer and the purchaser.

S4.

S1. Grain Size
S1.1 When a grain size range is required, it shall be
specified in the ordering information, and shall be determined by an agreed-upon method from Test Methods
E 112.

Fracture Toughness

S4.1 Specific fracture toughness requirements are levied by certain sections of the ASME Boiler and Pressure
Vessel Code. Forgings in the permitted types shall comply
with the applicable code sections.

S1.2 Samples for grain size estimation shall be taken
from the tension test specimen location.

S4.2 The necessary code references toughness criteria
and test temperature data shall be included in the ordering
information.

S2. Rough Machining
S2.1 Rough machining shall be performed in the
sequence and manner as specified.
S5.

Ultrasonic Examination

S5.1 Ultrasonic examination of forgings shall be carried
out in accordance with Practice A 388 /A 388M.

S3. Impact Testing
S3.1 Charpy V-notch test specimens shall be taken
from the same location and in the same orientation as
tension test specimens. The number of specimens, minimum energy values, and test temperature(s) shall be as
specified.

S5.2 Acceptance criteria shall be specified and shall
be in accordance with the applicable Code or purchaser’s
specification and shall be included as part of the ordering
information.

--``,,````,,```,```,,``,,`,,`,,`-`-`,,`,,`,`,,`---

706
Copyright ASME International
Provided by IHS under license with ASME
No reproduction or networking permitted without license from IHS

Licensee=Chevron Corp/5912388100
Not for Resale, 08/27/2008 14:59:35 MDT